Meningococcal Vaccines: College Students and Pilgrims
Abstracts & Commentary
Synopsis: The largest known outbreak of serogroup W-135 meningococcal disease occurred in pilgrims returning from the Hajj and their close contacts. This occurred despite Saudi Arabia’s requirement for immunization against Neisseria meningitidis in pilgrims, and demonstrates limitations in the current vaccine.
Sources: CDC. Serogroup W-135 meningococcal disease among travelers returning from Saudi Arabia—United States, 2000. MMWR Morb Mortal Wkly Rep 2000;49(16): 345-346; CDC Prevention and control of meningococcal disease: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 2000;49(RR07):1-10; CDC. Meningococcal disease and college students: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 2000;49(RR07):11-20.
In the june 30, 2000 issue of Morbidity and Mortality Weekly Report, the CDC published recommendations of the Advisory Committee on Immunization Practices on the prevention and control of meningococcal disease, specifically addressing meningococcal disease in college students. Immunization is recommended for high-risk persons, including persons with terminal complement component deficiencies, asplenia, and persons with routine occupational exposure to Neisseria meningitidis in solutions that could become airborne. College freshmen, especially those living in dormitories, are felt to be at modestly increased risk for meningococcal disease. The risk should be discussed with the students and their parents, and meningococcal vaccine should be offered to those interested. Certain travelers and expatriates, in particular travelers to the "meningitis belt" of Africa during the dry season (December to June), may have an increased risk and the vaccine should be recommended.
In April 2000, cases of meningococcal disease, many due to serogroup W-135, were reported from several countries among pilgrims returning from the Hajj in Saudi Arabia and their close contacts. This year’s Hajj concluded on March 17. As of April 20, 2000, three cases of serogroup W-135 meningococcal disease were identified in the United States among the 11,000 pilgrims who had traveled to Mecca from the United States (see also Kemper CA. Infect Dis Alert 2000;19:128).
The three cases of meningococcal disease were all reported by the New York City Department of Health. One patient was a pilgrim who had been vaccinated with the meningococcal quadrivalent polysaccharide vaccine. Another patient was a household contact of a pilgrim. The third patient may have interacted with returning pilgrims or their families five days prior to falling ill. Serogroup W-135 N. meningitidis was cultured from blood in two patients, and from joint fluid in the third patient. Two of the isolates have been confirmed by the CDC, and were subserotype P15,2 by PorA gene sequencing.
Comment by Lin H. Chen, MD
A prior outbreak of group A meningococcal meningitis occurred in pilgrims to Mecca, Saudi Arabia, in 1987, leading to Saudi Arabia’s requirement for meningococcal vaccine in persons entering pilgrims.2 Approximately 1.3 million pilgrims traveled to the Hajj in Saudi Arabia this year. As of May 12, 2000, 330 cases of meningococcal disease in returning pilgrims and their close contacts have been reported to the WHO.7 Fifty of the 225 cases reported from Saudi Arabia as of April 27 were confirmed to be serogroup W-135, and more than 40 of the cases from France, United Kingdom, Oman, Netherlands, Morocco, and the United States were confirmed to be serogroup W-135.4-7
This is the largest known outbreak of W-135 meningococcal disease. Laboratory surveillance in the United States has shown that serogroup W-135 accounted for only 4% of cases, whereas serogroups C, B, and Y are the more common causes of meningococcal disease, associated with 35%, 32%, and 26% of cases, respectively.3
Currently, the quadrivalent polysaccharide vaccine is the only meningococcal vaccine distributed in the United States and covers serogroups A, C, Y, and W-135. Some of the pilgrims may have received the bivalent A and C vaccines in other countries. Clinical efficacies are felt to be 85-100% for meningococcal serogroup A and C polysaccharide vaccines.1 Clinical efficacy of W-135 polysaccharide vaccine is unclear. The patient who had received the quadrivalent vaccine illustrates possible failure of this vaccine, although the host factors are not known. The other cases demonstrate that vaccines do not prevent or eradicate carriage of N. meningitidis.
This outbreak of serogroup W-135 meningococcal disease supports the requirement for meningococcal vaccine in travelers participating in pilgrims. It underscores the importance of using a quadrivalent vaccine for optimal protection. However, the efficacy of the W-135 polysaccharide vaccine needs further evaluation. Conjugate vaccines that are under development may improve protection against meningococcal disease in the future.8 (Dr. Chen is Clinical Instructor, Harvard Medical School and Travel/Tropical Medicine Clinic, Lahey Clinic Medical Center, Cambridge, Mass.)
References
1. CDC. Control and prevention of meningococcal disease and control and prevention of serogroup C meningococcal disease: Evaluation and management of suspected outbreaks/recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 1997;46(RR-5):1-21.
2. Moore PS, et al. Group A meningococcal carriage in travelers returning from Saudi Arabia. JAMA 1988; 260(18):1686-2689.
3. Rosenstein NE, et al. The changing epidemiology of meningococcal disease in the United States, 1992-1996. J Infect Dis 1999;180:1894-1901.
4. World Health Organization. Meningococcal disease in France, United Kingdom, Oman, Saudi Arabia, Netherlands. Available at http://www.who.int/emc/outbreak_news/n2000/april/21a%20apr2000.html.
5. World Health Organization. Meningococcal disease in Saudi Arabia and the Netherlands—update. Available at http://www.who.int/emc/outbreak_news/n2000/ april/27apr2000.html.
6. World Health Organization. Meningococcal disease in Singapore, Indonesia, Iran and Morocco. Available at http://www.who.int/emc/outbreak_news/n2000/may/3may2000.html.
7. World Health Organization. Meningococcal disease, serogroup W135—update. Available at http://www. who.int/emc/outbreak_news/n2000/12may2000.html.
8. Perkins BA. New opportunities for prevention of meningococcal disease. JAMA 2000;283:2842-2843.
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